Biological Sample Handling
In biological research, various biological samples need to be processed, such as cell cultures, serums, bacterial cultures and so on. Through filtration, cell debris, bacteria, viruses and other impurities in the samples can be effectively removed to improve the purity and quality of the samples.
Solution Preparation and Mixture Separation
Laboratories often need to prepare various solutions or mixtures and separate them. Filtration removes solid particles or suspended matter, such as sediments or impurities, from solutions, making them clearer and more transparent and ensuring the accuracy of subsequent experimental operations and the reliability of results.
Environmental and Water Quality Monitoring
In the field of environmental science and water quality monitoring, filtration is used to collect environmental samples such as water and gas samples and remove contaminants such as particles, microorganisms and organic matter from them.
This reduces interfering substances in the samples, improves the accuracy and reliability of subsequent analysis and testing, and provides important technical support for environmental protection and water quality monitoring.
Selection of laboratory filters need to pay attention to 4 points
In the laboratory, usually filtered are organic molecules solution, or laboratory cell culture dishes and other biological products, in addition to gas environmental samples, etc., choose the laboratory filter usually need to pay attention to the following 4 points of skill.
Point 1: Laboratory Filter Materials
The primary consideration in laboratory filter selection is the type of filter material.
Filters |
Material |
Depth filters |
Typically made of thick, porous materials such as cellulose or fiberglass, they are suitable for high flow and low pressure applications. They provide effective filtration by trapping particles on the filter surface and within the structure. |
Trail Etch Filters |
Made of high quality polycarbonate film with a variety of precise pore sizes for accurate particle separation and retention. Avoids particles from being trapped within the filter structure during the filtration process, providing higher filtration accuracy compared to depth filters. |
Microfiltration membranes |
Typically made of various polymers with a spongy structure. Thin microporous membranes are used to separate or retain particles on the surface of the membrane, acting as a cut-off, and are mostly filter membranes with a sterilizing filter effect that strictly meets the high standards of the laboratory industry. |
Ultrafiltration membranes |
A semi-permeable membrane designed to retain large molecules when a driving force such as pressure is applied. Ultrafiltration membranes can be used in the laboratory to separate and purify larger molecules in solution. |
Chromatography Membrane |
Although not filters per se, they are manufactured in a similar manner to microfiltration membranes. They are highly specialized stationary phase matrices, functionalized by ion exchange or affinity ligands, used for purification and refinement of biomolecules based on their chemical and physical properties. |
Point 2: Filter Pore Size
We all know that the pore size of a filter must be smaller than the size of the particles that need to be filtered, i.e., the pore size determines the range of sizes of particles that can pass through or be trapped in the filter.
The exact pore size required for a particular application will depend on the nature of the sample, the purity required and the throughput.
In some cases, it may be necessary to perform multiple filtration steps or use filters with different pore sizes. In some cases, it may be necessary to perform multiple filtration steps or use filters with different pore sizes to ensure that higher precision filtration requirements are met and that consistency before and after filtration is achieved.
Below are common filter pore sizes for several types of filters:
- Depth filtration(0.7-100 µm) is used to remove visible and smaller particles, or to remove cells after harvesting in a bioreactor.
- Microfiltration (0.1-10 µm) retains particles such as bacteria, yeast and large cells in the surrounding liquid and is commonly used for clarification, sterilization and contaminant removal.
- Ultrafiltration (1-100 nm) membranes retain large molecules such as proteins, nucleic acids, viruses and nanoparticles in liquid samples. These filters are used for concentration of biomolecules, buffer exchange and desalination, and also for protein removal.
- Chromatography membranes (up to hundreds of nanometers) have a macroporous structure that allows purification of not only proteins and nucleic acids, but also larger protein complexes and viruses.
- Reverse osmosis (less than 1 nm) is used to remove salts and other small molecules from water and other liquids, e.g. to prepare ultrapure water.
Point 3: Chemical Compatibility
A very important factor to evaluate when considering the choice of filter material is chemical compatibility. This involves evaluating the tolerance of the filter membrane to various substances such as acids, bases, and organic solvents.
The filter material should be chemically and physically compatible with the content and composition of the sample being filtered. For example, certain filter housings are more chemically resistant than others.
Filter materials that are incompatible with process conditions may shrink, expand or deform, for example, they are intolerant to high temperatures, repulsive to strong acids and bases, and other reasons. This ultimately leads to poor filtration or even damage to the filter.
We often see “low protein adsorption”, what does protein adsorption mean here? Some filters may be considered “sticky” to certain proteins; this means that proteins will be adsorbed to the membrane, reducing the final yield.
Sanitek offers filters in a variety of materials that can be customized to the specific chemistry of the fluid being filtered.